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Value analysis (VA)
Valve Device that opens and closes the combustion
chamber of an internal-combustion engine to admit the fuel-air
mixture or exhaust the gases.
Valve Float
A high-rpm engine condition in which the valve lifters
lose contact with the cam lobes because the valve springs are
not strong enough to overcome the momentum of the various valvetrain
components. The onset of valve float prevents higher-rpm operation.
Extended periods of valve float will damage the valvetrain.
Valve Lifter
Also called a "valve follower": the cylindrically
shaped component that presses against the lobe of a camshaft
and moves up and down as the cam lobe rotates. Most valve lifters
have an oil-lubricated hardened face that slides on the cam lobe.
So-called "roller lifters", however, have a small roller
in contact with the cam lobe: thereby reducing the friction between
the cam lobe and the lifter.
Valves
(e.g. 24 valves) Signifies the total intake and exhaust
valves in an engine. For example, a 24-valve V-6 would have
4 valves per cylinder 24/6=4. A 16-valve V-8 would have 2 valves
per cylinder 16/8=2. More valves allow the engine to breathe
better at high RPM and produce more power.
Valvetrain
The collection of parts that make the valves operate.
The valvetrain includes the camshaft(s) and all related drive
components, the various parts that convert the camshaft's rotary
motion into reciprocating motion at the valves, and the valves
and their associated parts.
Vapor lock
Vapor lock occurs when an engine gets so hot, it boils the fuel
travelling through the fuel lines. This creates vapor, which
then prevents the engine from running.
VEE Engine
An engine with cylinders arranged in two rows at an
angle to the common crankshaft. Has a "V" shape
when viewed from the front.
Vehicle Identification Number
(VIN) Number assigned to a vehicle
by the manufacturer primarily for registration and identification
purposes (consisting of numerals and letters).
V-Rod
The Harley-Davidson VRSCA V-Rod is a liquid-cooled, 1130cc V-Twin
cruiser. The engine was designed by Porsche.
V-Twin
A V-Twin is an engine having two cylinders placed at an angle
to each other in the shape of a V.
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